Apparatus for spinning synthetic {37 islands-in-a-sea{38 {0 type composite filaments

ABSTRACT

A spinning apparatus valuable for obtaining uniform &#39;&#39;&#39;&#39;islandsin-a-sea&#39;&#39;&#39;&#39; type composite filaments comprises a uniting chamber comprising a funnel-shaped space having a converging angle of at most 75*. The apparatus may further include means for supplying the sea constituent polymeric liquid into a central portion and an outside portion of the uniting chamber, and means for incorporating the island constituent polymeric liquid with the sea constituent polymeric liquid in an eccentric manner. These means are effective for maintaining the &#39;&#39;&#39;&#39;islands-in-asea&#39;&#39;&#39;&#39; type composite stream in the uniting chamber at a favorable equilibrated condition for a long spinning period.

United States Patent Okamoto et a1.

[54] APPARATUS FOR SPKNNING SYNTHETIC ISLANDS-lN-A-SEA TYPE COMPOSITE FHLAMENTS [72] Inventors: Miyoshi Okamoto, Osaka; Keiichi Ashida, Kyoto; Koji Watanabe; Shinzo Taniguchi, both of Otsu, all of Japan [73] Assignee: Toray Industries, llnc., Tokyo, Japan [22] Filed: June 24, 1970 [21] Appl. N0.: 49,244

52 us. Cl. .425/131, 264/176 F [51] Int. Cl. ..D01d 3/00 [58] Field of Search....l8/8 SC, 8 SS; 264/204, 176 F [56] References Cited UNITED STATES PATENTS 3,500,498 3/1970 Fukuma et al. ..18/8 SC 3,188,689 6/1965 Breen ..l8/8 SC 3,538,544 11/1970 Ullman ..l8/8 SC 2,341,555 2/1944 Jones ..l8/8 SS 2,985,911 5/1961 Griset ..18/8 SS 3,006,026 10/1961 Martin et a1 ..l8/8 SS [is] 3,692,423 [451 Sept. 19, 1972 3,308,507 3/1967 Black ..18/8 SS X 3,531,368 9/1970 Okamoto et a1 ..l8/8 SC X 3,537,135 ll/l970 Santangelo ..l8/8 SS 3,559,237 2/ 1971 Den Biggelaar et al....l8/8 SC Primary Examiner-J. Spencer Overholser Assistant Examiner--Michael 0. Sutton Attorney-Robert E. Burns and Emmanuel J. Lobato [57] ABSTRACT A spinning apparatus valuable for obtaining uniform islands-in-a-sea type composite filaments comprises a uniting chamber comprising a funnel-shaped space having a converging angle of at most 75. The apparatus may further include means for supplying the sea constituent polymeric liquid into a central portion and an outside portion of the uniting chamber, and means for incorporating the island constituent polymeric liquid with the sea constituent polymeric liquid in an eccentric manner.

These means are effective for maintaining the islands-in-a-sea type composite stream in the uniting chamber at a favorable equilibrated condition for a long spinning period.

14 Claims, 20 Drawing Figures PATENTEUSEP 19 m2 SHEET 1 0F 5 PRIOR ART APPARATUS FOR SPINNING SYNTHETIC ISLANDS-lN-A-SEA TYPE COMPOSITE FILAMENTS The present invention relates to an apparatus for spinning synthetic composite filaments, more particularly, relates to an apparatus for spinning synthetic islands-in-a-sea type composite filament containing a plurality of uniform superfine filamentary constituents extending independently from each other along the length of the composite filament.

The term composite filament as used herein refers to a filament being composed of at least two synthetic polymeric constituents different from each other. The constituents are incorporated into a filament body in a side-by-side or core-in-sheath form.

The term islands-in-a-sea type composite filament as used herein refers to specific core-in-sheath type composite filaments, which are composed of a plurality of superfine filamentary constituents (island constituents) and another filamentary constituent (sea constituent). The island constituents extend independently from each other along the length of the composite filament in a superfine filament form and the sea constituent incorporates the island constituents into a filament body by filling spaces between the island constituents.

Generally, the islands-in-a-sea type composite filaments are spun through a specific spinning process in which, firstly, a plurality of polymeric island constituent streams and a polymeric sea constituent stream are separately formed. Secondly, every island constituent stream is incorporated with a portion of the sea constituent stream so as to form a plurality of composite streams in the side-by-side" or core-insheath" form. Thirdly, the composite streams are united into an islands-in-a-sea type composite stream in which the sea constituents in the composite streams adhere to each other and fill spaces between the island constituents and fourthly, the islands-in-a-sea type composite streams are extruded through a spinning orifice to form an islands-in-a-sea type composite filament.

The islands-in-a-sea type composite filaments have a high rigidity and are useful for preparing bundles of superfine filaments having a very small fineness by removing the sea constituent. The bundles of the superfine filaments are valuable for preparing non-woven fabrics or synthetic leather having a very soft hand feelmg.

Generally, the island constituent is selected from the fiber forming linear polymers such as polyamides, for example nylon 6, nylon 66, nylon 12, and nylon 910, polyesters such as polyethylene terephthalate and its copolycondensation products, polyolefins such as polypropylene and polyethylene and acrylic polymers such as polyacrylonitrile and its copolymers.

The sea constituent is selected from styrene type polymers, such as polystyrene, styrene-acrylonitrile copolymers, styrene-methylmethacrylate copolymers and styrene-acrylonitrile-methyl methacrylate copolymers which have a relatively lower viscosity than that of the island of the constituent under a spinning condition, in general.

In the conventional apparatus for carrying out the above-stated process, the composite streams consisting of an island constituent stream and a sea constituent stream are united in a funnel-shaped uniting chamber. The composite streams are separately supplied into an upper opening of the funnel-shaped chamber and downstreamly toward the orifice located at a lower opening of the uniting chamber while being united into an islandsin-a-sea type composite stream and decreasing its cross-sectional diameter.

Needless to say, it is desirable that the islands-in-asea type composite stream in the uniting chamber is maintained in a constantly equilibrated form for a long spinning period for obtaining a product having uniform quantities. However, the conventional uniting chamber has the following disadvantages. Even if the outlets for supplying the composite streams are located in an even arrangement and the composite streams are supplied into the uniting chamber through the outlets at a constant output, after long continuous spinning period the following faults occur,

1. variance of location of the island constituent streams in the islands-in-a-sea type composite stream,

2. deformation of the cross-sectional profile of the island constituent streams, particularly, those located outlying or approaching the axis of the uniting chamber, and

3. exposure of the island constituent streams located outlying the axis of the uniting chamber outside the sea constituent stream.

The above-stated disadvantages result in an islandsin-a-sea type composite filament having a nonuniform fineness and uneven cross-sectional profile in which the island constituents have non-uniform fineness and uneven cross-sectional profile and are unevenly located in the sea constituent. The uneven composite filaments exhibit a tendency of the island constituent exposed outside to separate easily from the sea constituent and result in uneven dying.

An object of the present invention is to provide an apparatus for spinning synthetic islands-in-a-sea type composite filaments having a constantly equilibrated location of the island constituent and sea constituent for long continuous spinning periods.

Another object of the present invention is to provide an apparatus for spinning synthetic islands-ima-sea type composite filaments containing island constituents having a uniform fineness and an even cross-sectional profile.

The objects of the present invention can be achieved by providing a spinneret comprising, in combination,

1. a first passage for supplying sea constituent polymeric liquid from its supply source, an outlet of the first passage being branched to a plurality of branched ends for distributing the sea constituent polymeric liquid,

2. a plurality of second passages for supplying island constituent polymeric liquid from its supply source, outlets of the second passages open into corresponding branched ends of the first passage so as to incorporate the sea constituent polymeric liquid streams supplied through the branched ends of the first passage with the island constituent polymeric liquid streams supplied through the second passages into a plurality of composite streams,

3. a uniting chamber for uniting the composite streams into an islands-in-a-sea type composite stream, the uniting chamber comprises a substantially funnel-shaped space having a converging angle of at most 75 and 4. a spinning orifice connected to a lower end of the uniting chamber.

The uniting chamber of the spinneret of the present invention may further comprise a cylindrical space connected with the upper opening of the funnel-shaped space. The cylindrical space has a height (X) in mm satisfying the following relationship:

wherein represents a converging angle in degrees of the funnel-shaped space.

The incorporating of the sea and island constituent polymeric streams may be carried out through third passages.

Each inlet of the third passages opens in a corresponding branched end of the first passage in a position facing a corresponding outlet of the second passage. Each outlet of the third passages is fluidly connected to the uniting chamber. The third passages allow passing of a composite stream which is formed from the sea constituent and island constituent at the branched end of the first passage to the uniting chamber.

- The present invention includes an improvement effective for achieving the purpose. A plurality of fourth passages for directly supplying the sea constituent into an outside portion of the islands-in-a-sea type composite stream in the uniting chamber are formed in the spinneret. The fourth passages are very effective for preventing the island constituent located at the outlying portion of the uniting chamber, from deformation into a flat form and exposure outside the sea constituent.

Further, the present invention includes another improvement effective for achieving the purpose. At least one fifth passage is formed in the spinneret for directly supplying the sea constituent into a central portion of the isIands-in-a-sea type composite stream in the uniting chamber. The fifth passage is very effective for preventing the island constituent located on and/or around the axis of the uniting chamber from deformation into an irregular form.

Furthermore, the present invention includes still another improvement effective for achieving the purpose. In the improvement, each outlet of the second passages located outlying the axis of the uniting chamber is disposed in an eccentrically located manner with respect to an inlet of a corresponding third passage. That is, the second passages outlets are arranged in a position approaching the axis of the uniting chamber with respect to a center of each of the third passages inlets. The improvement is effective for preventing the island constituent located outlying the uniting chamber axis from adhering with each other and exposure outside the sea constituent.

The present invention will be explained in the following description with reference to the accompanying drawings in which:

FIG. 1 shows a cross-sectional profile of a typical islands-in-a-sea" type composite filament,

FIG. 2 shows a cross-sectional profile of an undesirably deformed islands-in-a-sea type composite filament,

FIG. 3 shows a cross-sectional profile of another undesirably deformed islands-in-a-sea type composite filament,

FIG. 4 shows a sectional view of a conventional uniting chamber,

FIG. 5 shows a sectional view of an embodiment of a spinning apparatus according to the present invention,

FIG. 6 shows a sectional view of an embodiment of the uniting chamber according to the present invention,

FIG. 7 shows a sectional view of another embodiment of the uniting chamber according the present invention,

FIG. 8 shows a partial-sectional view of the spinning apparatus indicated in FIG. 5,

FIG. 9 shows a partial-sectional view of another spinning apparatus according to the present invention,

FIG. 10 shows a sectional view of still another spinning apparatus according to the present invention,

FIG. 11 shows a sectional view of still another spinning apparatus according to the present invention,

FIG. 12A shows a sectional view of another spinning apparatus according to the present invention,

FIG. 12B shows cross-sectional views of composite streams formed in the apparatus of FIG. 12A,

FIG. 13A shows a sectional view of another spinning apparatus according to the present invention,

FIG. 133 shows cross-sectional views of composite streams formed in the apparatus of FIG. 13A,

FIG. 14A shows a sectional view of another spinning apparatus according to the present invention,

FIG. 148 shows cross-sectional views of composite streams formed in the apparatus of FIG. 14A,

FIG. 15 shows a cross-sectional view of composite streams formed in another apparatus according to the present invention,

FIG. 16A shows a sectional view of still another spinning apparatus according to the present invention, and

FIG. 16B shows cross-sectional views of composite streams formed in the apparatus of FIG. 16A.

Referring to FIG. 1, the islands-in-a-sea type composite filament l is composed of 16 island constituents 2 and a sea constituent 3, each of the island constituents 2 has a uniform cross-sectional profile and are embedded in the sea constituent 3 in a prescribed location. FIG. 2 shows an irregular islands-in-a-sea" type composite filament 4 in which 10 island constituents 7 located outlying the cross-sectional center 8 have a flat profile, one island constituent 5 located at the center 8 has a circular profile and 5 island constituents 6 located approaching the center 8 have a cam-shaped profile wherein a portion approaching the center 8 projects toward the center 8.

FIG. 3 shows another irregular islands-in-a-sea type composite filament 10 in which ten island constituents 9 located outlying the cross-sectional center 8 have a flat profile and are exposed outside the sea constituent 3. The irregular composite filaments as shown in FIGS. 2 and 3 result after spinning for a long time using the conventional spinning apparatus and causes formation of a bundle consisting of uneven superfine filaments by removing the sea constituent, and also causes uneven processing properties of the composite filament.

Particularly, the irregular composite filament as indicated in FIG. 3 has an undesirable tendency to separate the exposed island constituents 9 from the sea constituent 3 during processing such as drawing, winding, carding and needle punching.

It is not yet satisfactorily clarified as to why such deformation of the island constituents occurs after a long continuous spinning period. We assume that cause of the deformation relates to the following facts.

That is, when the composite streams, united into an islands-in-a-sea form, flow through the uniting chamber having a substantially funnel-like shape while decreasing the cross-sectional area thereof, there are certain differences between lengths of paths and shearing velocities for a portion located near the axis of the uniting chamber and a portion located near the inside surface of the uniting chamber, the former has a shorter length and a smaller shearing velocity than those of the latter.

REferring to FIG. 4, the conventional uniting chamber 11 has a relatively large converging angle 0. In this case, it is obvious that the portion 13 near the axis 12 has a path length shorter than that of the portion 14 near the inside surface 15. Further, the portion 14 is forced at a shearing velocity larger than that of the portion 13 in consideration of frictional force between the flowing liquid and the inside surface. Accordingly, the portion 13 flows at a linear velocity higher than that of the portion 14, this results in the portion 14 having a remaining time in the uniting chamber longer than that of portion 13.

Further, we assume that the cause of the deformation relates to the difference between viscosities of the island constituent and the sea constituent. Generally, the island constituent polymer has a viscosity higher than that of the sea constituent polymer. In the case where the polymeric streams having different viscosities from each other flow under a high shearing velocity condition through the uniting chamber, equilibrium of the constituent streams in the islands-in-a-sea type composite stream is unstable. The unstable equilibrium causes an unstable spinning process and non-uniform product qualities.

For preventing the above mentioned disadvantages, it is desirable that the uniting chamber has a substantially uniform path length and the constituent streams flow, substantially, in the same direction. However, the spinneret satisfying the above-stated conditions has the following drawbacks;

l. prolongation of remaining time of the polymeric liquid in the uniting chamber and this results in deterioration of the resultant product quality,

2. requirement of a large depth for the spinneret.

Referring to FIG. 5, a spinning pack 21 contains supply means 22 for supplying the island and sea constituent polymeric liquids from its supply sources which are not shown in the drawing, and a spinneret 23. The supply means 22 is provided with a sea constituent polymeric liquid supply conduit 24 connected to the corresponding supply source, an island constituent polymeric liquid supply conduit 25 connected to the corresponding supply source, an annular chamber 26 for distributing the sea constituent polymeric liquid to the spinneret 23 and a chamber 27 for distributing the island constituent polymeric liquid into the spinneret 23. The chamber 26 is fluid-tight and separated from the chamber 27 by an annular packing 28.

The spinneret 23 includes four metal plates 29, 30, 31 and 32 for forming at least one spinning unit, for example, four units as indicated in FIG. 5. A first passage 34 is formed between the second and third plates 30 and 31 as indicated in the drawing. An inlet of the first passage 34 is connected to the annular chamber 26 through supply passages 35 formed in the first and second plates 29 and 30. An outlet of the first passage 34 is branched to a plurality of branched ends 20. Numerous second passages 33, for flowing the island constituent polymeric liquid, are formed in the first plate 29 so as to connect with the chamber 27. A plurality of third passages 36 are formed from apertures 37 formed in the third plate 31 and pipes 38 attached on the third plate 31. The lower ends of the pipe 38 are connected with the upper ends of the aperture 37. The upper ends of the pipes 38 face the lower ends of the second passage 33 in the branched end portions of the first passaged. Uniting chambers 39 are formed in the fourth plate 32 and each of the uniting chambers 39 is connected with several lower ends of the third passages 36. The uniting chambers 39 have a substantially funnel-shape and their lower ends are connected with spinning orifices 40. The two or more spinning units may be arranged in the spinneret at will, for example, on one or more concentric circles at a predetermined interval.

Referring to FIG. 6, the uniting chamber 39 has a substantially funnel-shaped space 42. The space 42 has a converging angle 6 of at most The converging angle 0 not exceeding 75 is so small that the conventional uniting chamber never has this converging angle of 75 or less, and is effective for gradually decreasing the diameter of the united composite streams passing through the uniting chamber. Such gradual decreasing of the diameter is effective for uniformly uniting the composite streams in a stabilized condition. The united composite streams are extruded into an islands-in-a-sea type composite filament form through the orifice 40.

Referring to FIG. 7, the uniting chamber 39 is composed of a cylindrical space 41 having a height X in mm and a funnel-shaped space 42 having a converging angle 0 in degree. The cylindrical space 41 is an inlet for receiving the composite streams supplied through the third passages 36 indicated in FIG. 5 and effective for stabilizing the uniting condition of the composite streams and for relaxing the shearing force produced on the composite streams by contacting with the inside wall 43. Also, the cylindrical space 41 is effective for preventing the composite streams from deformation during uniting with each other. The funnel-shaped space 42 is effective for uniting the composite streams into an islands-in-a-sea type composite stream under a favorable condition while narrowing the cross-section thereof and supplying the narrowed stream into the orifice 40.

The uniting chamber 39 of the present invention satisfies the following inequality relating to the height X and the converging angle 0:

If the uniting chamber does not satisfy the above inequality, the disadvantages as stated hereinbefore can not be avoided.

If the uniting chamber does not include the cylindrical space, that is, value of X is zero, value of must be smaller than 75 according to the above-mentioned inequality. Preferably, the converging angle 6 is smaller than 60. When the diameter of an upper opening of the uniting chamber, which does not include the cylindrical space, is 20 mm and 6 is 60, the height of the uniting chamber is approximately mm. If, the uniting chamber is provided with a cylindrical space having a height of mm, the converging angle 0 of the funnelshaped space is in a range from 14.8 to 178. When the converging angle 0 is 120, which belongs in the abovementioned range, the height of the funnel-shaped space is approximately 5.7 mm. Consequently, the height of the uniting chamber is 10 5.7 =l5.7 mm which is smaller than that of the above-stated uniting chamber not having a cylindrical space. That is, it is obvious that provision of the cylindrical space for the uniting chamber is effective for lowering the thickness of the fourth plate 32 containing the uniting chambers.

The island constituent polymeric liquid is fed from its supply source into the chamber 27 through the conduit 25 and distributed into the second passages 33. The sea constituent polymeric liquid is fed from its supply source into the chamber 26 through the conduit 24 and further fed into the first passage 34 through the passage 35. The island constituent polymeric liquid streams extruded through the lower openings of the second passages 33 pass across the spaces between the lower ends of the passages 33 and the upper ends of the passages 36 and then are introduced into the third passages 36.

Also, the sea constituent polymeric liquid stream in the first passage 34 is distributed into the third passage through the upper opening thereof and incorporated with the island constituent polymeric liquid stream into a composite stream form. In the spinneret indicated in FIG. 5, the lower opening of the second passage 33 has an area smaller than that of the upper opening of the third passage 36 and concentrically faces the upper opening of the third passage 36. Therefore, the island constituent streams are concentrically embedded in the sea constituent streams in a core-in-sheath type form. The composite streams thus formed are supplied in parallel into the uniting chamber 39 through the lower openings of the third passages 36.

The composite streams thus supplied are united by adhering with each other into an islands-in-a-sea type composite stream and flow down through the unit ing chamber 39 while decreasing the cross-sectional area of the islands-in-a-sea type composite stream. Since the uniting chamber 39 of the present invention satisfies the inequality indicated hereinbefore, the flowing down of the islands-in-a-sea type composite stream can be carried out at a favorable condition.

The isiands-in-a-sea type composite stream is extruded through the spinning orifice 40 into an islandsin-a-sea type composite filament form.

Referring to FIG. 8, the sea constituent stream supplied through the first passage 34 upwardly flows through a space 50 surrounding the pipe 38 and is concentn'cally or eccentrically incorporated with the island constituent stream supplied through the second passage 33 in the branched end portion 20.

Referring to FIG. 9, the island constituent polymeric liquid streams supplied through the second passages 33 pass to the uniting chamber through a plurality of conduits 51 inserted into the second plate 30 and third plate 31. The sea constituent polymeric liquid stream supplied through the first passage 34 is distributed into a plurality of outlet portions 52 branched from the first passage 34 and surrounding the conduits 51. Each of the distributed streams is discharged into the uniting chamber while concentrically or eccentrically incorporating with the island constituent streams discharged through each of the conduits 51 into a composite stream.

REferring to FIG. 10, the third passages 36 are located around the axis 12 of the uniting chamber 39, fourth passages 61 are located outlying the axis 12 so as to surround the third passage 36. The fourth passages 61 directly connect the first passage 34 to the uniting chamber 39. Thus, through the fourth passages 61, the sea constituent liquid is supplied into a peripheral portion of the islands-in-a-sea type composite stream flowing through the uniting chamber 39 so as to thicken the sea constituent layers thickness L at the peripheral portion as indicated in FIG. 1. This is effective for preventing the island constituent streams outlying the axis 12 from exposure outside the sea constituent stream and deformation.

Referring to FIG. 11, a fifth passage 62 is formed on the axis 12 and directly connects the first passage 34 to the uniting chamber 39. The sea constituent is supplied to the central portion of the islands-in-a-sea" type composite stream through the fifth passage 62. This is effective for preventing the island constituent streams approaching the axis 12 from deformation and for equilibrating the location of the island constituent streams in the islands-in-a-sea composite streams with each other. The fifth passage 62 may be located on the axis 12 as indicated in FIG. 11. Also, a plurality of fifth passages may be located near the axis 12. Projection 63 is projected in the first passage 34 and effective for stabilizing the stream passing through the fifth passage 62.

Referring to FIG. 12A, each of conduits 71a, 7 lb and 710 for passing the island constituent liquid has the same diameter as each other. La, Lb and Le represent thicknesses of spaces between the outside wall of conduits 71a, 71b and 71c and the inside wall of the branched end portions 72a, 72b and 720 of the first passage 34 for passing the sea constituent liquid, respectively. In the drawing, a relation between the thicknesses La, Lb and La is as follows.

Each conduit 71a, 71b and 710 is concentrically positioned with respect to the branched end portions 72a, 72b and 7 20, respectively.

In FIG. 12B, the configurations 73a, 73b and 73c show cross-sectional profiles of composite streams obtained from sea constituent streams passed through the branched end portions 72a, 72b and 720 of the first passage 34 and island constituent streams passed through the conduits 71a, 71b and 71c, respectively. In

the cross-sectional profiles 73a, 73b and 73c, the island constituents 74a, 74b and 74c, are concentrically embedded in the sea constituents 75a, 75b and 75c, respectively. The cross-sectional profile 730 has a thickness la of the sea constutuent stream, profile 73b a thickness lb and profile 730 a thickness Ic, and a relation among la, lb and lc is as follows:

Therefore, the composite stream oulying the axis 12 of the uniting chamber 39 has the largest thickness 1 a of the sea constituent stream and the composite stream approaching the axis 12 has the smallest thickness lc.

Such arrangement of the composite streams 73a, 73b and 730 is valuable for preventing the island constituent streams 740 located outlying the axis 12 from exposure outside the sea constituent stream.

Referring to FIGS. 13A and 138, the third passages 36d, 36s and 36f concentrically open in the branched ends 20d, 20e and 20f of the first passage 34, and face the second passages 33d, 33e and 33f, respectively. The diameters Ld, Le and Lf of the outlets 76d, 76e and 76f of the third passages 36d, 36c and 36f are different from each other. The outlet 76f of the third passage 36f located near axis 12 has the smallest diameter Lf and the outlet 76d of the passage 36d has the largest diameter Ld. Therefore, if viscosity of the island constituent stream is higher than that of the sea constituent stream, the composite streams 77d, 772 and 77f, as indicated in FIG. 133, have a relation between the thicknesses Id, le and If of the sea constituents 78d, 78c and 78f as indicated below.

ld le If The above-mentioned relation ld Is If is effective for perfectly embedding the island constituent streams distributed outlying the axis 12 in the sea constituent streams.

Referring to FIG. 14A, outlets of the second passages 82g, 82h and 82i having the same diameter open at corresponding branched end portions 83g, 83h and 83i having the same diameter as each other, respectively. Third passages 81g, 81h and 81i have the same diameter and these inlets face the outlets of the second passages, respectively. The outlet of the second passage 82i, located near the axis 12 of the uniting chamber 39, concentrically opens at the outlet of the corresponding branched end portion 83i, but the outlet of the second passage 82g located outlying the axis 12, and the outlet of the second passage 82h located just outside the passage 82i, eccentrically open at the outlets of the branched end portions 83g and 83h so that the outlets of the second passages located oulying the axis 12 position nearer the axis 12 with respect to centers of the outlets of the branched end portions of the first passages. The outlet of the second passage 82); may open concentrically at the outlet of the branched end portion of the first passage.

Referring to FIG. 1413, which shows cross-sectional profiles 84g, 84h and 84i of the composite streams passed through the third passages 81g, and 81h and 811, respectively, the island constituents 86g, 86h and 86i are embedded in the sea constituents 85g, 85h and 852' in core-in-sheath type forms, respectively. In the composite stream 841' and the island constituent 861' which passes through the third passage 81: located near the axis 12, is concentrically located in the sea constituent 851' and the thickness li of the sea constituent 851' is uniform. In the composite stream 84h, the island constituent 86h is eccentrically embedded in the sea constituent h, the thickness of the sea constituent 85h has a larger magnitude of lh at a side outlying the axis 12 of the uniting chamber 39. Also, in the composite stream 843, the thickness of the sea constituent 85g has a larger magnitude of lg at a side outlying the axis 12. A relation among lg, lh and I2 is as follows.

The island constituents in the composite streams outlying the axis 12 of the uniting chamber 39 may be incorporated with the sea constituents in a side-by-side" type form. Referring to FIG. 15, in the composite streams 90 located oulying the axis 12, the sea constituents 91 are arranged on the side away from the axis 12 but the island constituents 92 are arranged on the side toward the axis 12.

Such arrangement of the island and sea constituent streams in the composite streams is efiective for obtaining an islands-in-a-swa type composite filament in which the island constituents are perfectly embedded in the sea constituent without exposure thereof outside the composite filament.

Referring to FIG. 16A, the branched end portions 103j, 103k and 1031 of the first passage 34 have the same outlet area as each other. Also, the third passages l0lj 101k and 1011 have the same outlet area as each other.

However, the second passages 102j, 102k 1021 in which there is a relation between positions in a concentrical condition with respect to the branched end portions l03j, 103k and 1031, respectively, has diameters lj, Lk and Ll which are in a relation as indicated below.

Lj Lk e LI That is, cross-sectional area of the second passage 10lj outlying the axis 12 is largest and cross-sectional area of the second passage 1011 located near the axis 12 is smaller. In such arrangement, the resultant composite streams passed through the third passages 101 j, 101k and 1011 have cross-sections 104j 104k and 1041 as indicated in FIG. 168, respectively.

Referring to FIG. 168, the diameters of the crosssection 104j, 104k and 1041 are same as each other, that is, each of the cross-section 104j, 104k and 1041 has an area the same as each other, which area is represented as B. The cross-sections l06j, 106k and 1061 of the island constituent streams passed through the corresponding second passages 102j, 102k, 1021 and third passage 101j, 101k and 1011 have areas represented as Aj, Ak and Al, respectively, and these areas are in a relation as indicated below.

Aj Ak Al Bj Bk Bl Consequently, there are relations as follows:

and

(BAj) (B-Ak) a (B-Al) wherein (B-Aj), (B-Ak) and (B-Al) represent a cross-sectional area of the sea constituent streams 105;, 105k and 1051, respectively.

Therefore, the thicknesses lj, 1k and II of the sea constituent streams 1051', 1051 are in relation as follows:

and the island constituent streams l06j, 106k and 1061 are embedded in a concentrical relation with respect to the sea constituents 105j, 105k and 1051, respectively.

In such arrangement, the resultant islands constituents located outlying the cross-sectional center of the isiands-in-a-sea type composite filament have a fineness smaller than those of the others, and are perfectly embedded in the resultant sea constituent.

- The spinning apparatuses indicated in FIGS. 10 to l l and 12A, 13A, 14A. and 16A are effective for achieving the objects of the present invention, that is, for preventing the island constituents in the islands-in-a-sea type composite stream from deformation and exposure outside the islands-in-a-sea type composite stream for a long continuous spinning period. Further, these apparatuses are valuable for maintaining the location of the sea and island constituents in the islands-in-a-sea type composite streams at an equilibrated condition for long spinning period and obtaining a uniform islandsin-a-sea" type composite filament.

Several empodiments of the spinning apparatus comprising the means for forming a composite stream composed of the sea constituent stream and the island constituent stream were described in detail referring to the accompanying drawings hereinbefore. From the above description, it will he obviously understood that the conventional means for incorporating two constituent streams may be utilized for the purpose of the present invention, and the numerous composite streams prepared by the conventional incorporating means can be united into a complex conjugate stream in the uniting chamber according to the present invention at a favorable condition.

What is claimed is:

1. Apparatus for spinning islands-in-a-sea type synthetic composite filaments composed of a plurality of synthetic polymeric filamentary constituents (island constituents) fully embedded in a synthetic polymeric filamentary constituent (sea constituent) comprising at least one spinning unit which comprises, in combination, a housing, a plurality of superposed plate means assembled in said housing and comprising first, second and third plate means, with a first space above said first plate means and a second space between said first and second plate means,

said first plate means having formed therein a plurality of spinneret passages corresponding in number and arrangement to the island constituents of said composite filament, means for supplying island constituent polymeric liquid to said first space to extrude streams of said polymeric liquid through said spinneret passages, and second passages in alignment with said spinneret passages into which said spinneret passages discharge, said second passages being of larger diameter than the discharge ends of said spinneret passages,

said second plate means having a plurality of third passages aligned respectively with said second passages of said first plate and comprising tubes extending up into said second passages of said first plate means respectively to receive streams of said island polymeric liquid extruded by said spinneret passages and with an annular space around each said tube, means for supplying sea component polymeric liquid through said second space to said annular spaces to flow around said streams of island constituent polymeric liquid as they are extruded into said tubes to form composite streams each comprising a stream of island constituent polymer liquid surrounded by sea constituent polymer liquid, and

said third plate means having a cavity therein defining a uniting chamber into which all of said third passages of said second plate means discharge, said uniting chamber having a substantially funnelshaped space converging to a single spinning orifice constituting a discharge opening of said uniting chamber for uniting said composite streams into an islands-in-a-sea stream and gradually reducing the diameter of said islands-in-a-sea stream without deformation.

2. Apparatus according to claim 1, in which said first plate means comprises an upper plate in which said spinneret passages are formed, and a lower plate in which said second passages are formed, said upper and lower plates being contiguous face-to-face.

3. Apparatus according to claim 1, in which the angle of convergence of said funnel-shaped space is at most 4. Apparatus according to claim 1, in which said uniting chamber comprises a cylindrical space formed between the outlets of said third passages in said second plate means and said funnel-shaped space and satisfies the relation wherein X represents the height of said cylindrical space in mm and 6 represents the converging angle of said funnel-shaped space in degrees.

5. Apparatus according to claim 1, in which said second plate means has a plurality of fourth passages directly connecting said second space with said uniting chamber and located in an annular area of said second plate means surrounding the area in which said third passages are located, through which fourth passages said sea constituent polymer liquid is supplied to a peripheral portion of said uniting chamber,

6. Apparatus according to claim 5, in which said second plate means has at least one fifth passage directly connecting said second space with a central portion of said uniting chamber.

7. Apparatus according to claim 1, in which the outlet ends of said spinneret passages open concentrically into corresponding second passages.

8. Apparatus according to claim 1, in which all of said spinneret passages have the same cross sectional area and said second passages located farther from the uniting chamber axis have a larger cross sectional area that those located nearer to said axis.

9. Apparatus according to claim 1, in which all of said second passages have the same cross sectional area and said spinneret passages located farther from the uniting chamber axis have a smaller cross section than those located nearer said axis.

10. Apparatus according to claim 1, in which outlets of said spinneret passages located farther from the uniting chamber axis are disposed eccentrically of corresponding second passages, the axes of said spinneret passages being offset inwardly from the axes of said second passages in a direction toward the uniting chamber axis.

11. Apparatus according to claim 1, in which said tubes located farther from the uniting chamber axis have a larger inside cross sectional area than those located nearer said axis.

12. Apparatus for spinning islands-in-a-sea type synthetic composite filaments composed of a plurality of synthetic polymeric filamentary constituents (island constituents) fully embedded in a synthetic filamentary constituent (sea constituent), comprising at least one spinning unit which comprises, in combination, a housing, a plurality of superposed plate means assembled in said housing and comprising first, second and third plate means with a first space above said first plate means and a second space between said first and second plate means,

said first plate means comprising an upper plate having formed therein a plurality of spinneret passages corresponding in number and arrangement to the island constituents of said composite filament, and a contiguous lower plate having formed therein second passages in alignment with said spinneret passages into which said spinneret passages discharge, said second passages being of larger diameter than the discharge ends of said spinneret passages,

means for supplying island constituent polymeric liquid to said first space to extrude streams thereof through said spinneret passages of said upper plate into said second passages of said lower plate,

said second plate means having formed therein a plurality of third passages aligned respectively with said second passages of said first plate means, tubes set in said second passages of said first plate means and extending through said third passages of said second plate means, said tubes having an external diameter smaller than the diameter of said third passages to provide an annular passage between each said tube and the respective third passage,

means for supplying sea component polymeric liquid to said second space for extrusion through said annular passages,

and said third plate means having a cavity therein defining a uniting chamber into which all of said tubes and annular passages discharge to form a composite stream comprising separate island constituent streams surrounded by sea constituent streams, said uniting chamber having a first portion of cylindrical shape into which all of said tubes and annular passages discharge without cross sectional area reduction and a second portion having a substantially funnel-shaped space converging into a single spinning orifice, the proportions of said uniting chamber satisfying the relation:

9 1??? 7" wherein X represents the height of said cylindrical space in mm and 0 represents the converging angle of said funnel-shaped space in degrees, whereby said composite islands-in-a-sea stream is reduced in diameter while maintaining the relation of said islands in said sea.

13. Apparatus according to claim 12, in which the angle of convergence of said funnel-shaped space is at most 14. Apparatus according to claim 12, in which said tubes are all of the same cross sectional area and said third passages are of different cross sectional areas, said third passages farther from the uniting chamber axis being larger than those nearer said axis. 

1. Apparatus for spinning ''''islands-in-a-sea'''' type synthetic composite filaments composed of a plurality of synthetic polymeric filamentary constituents (island constituents) fully embedded in a synthetic polymeric filamentary constituent (sea constituent) comprising at least one spinning unit which comprises, in combination, a housing, a plurality of superposed plate means assembled in said housing and comprising first, second and third plate means, with a first space above said first plate means and a second space between said first and second plate means, said first plate means having formed therein a plurality of spinneret passages corresponding in number and arrangement to the island constituents of said composite filament, means for supplying island constituent polymeric liquid to said first space to extrude streams of said polymeric liquid through said spinneret passages, and second passages in alignment with said spinneret passages into which said spinneret passages discharge, said second passages being of larger diameter than the discharge ends of said spinneret passages, said second plate means having a plurality of third passages aligned respectively with said second passages of said first plate and comprising tubes extending up into said second passages of said first plate means respectively to receive streams of said island polymeric liquid extruded by said spinneret passages and with an annular space around each said tube, means for supplying sea component polymeric liquid through said second space to said annular spaces to flow around said streams of island constituent polymeric liquid as they are extruded into said tubes to form composite streams each comprising a stream of island constituent polymer liquid surrounded by sea constituent polymer liquid, and said third plate means having a cavity therein defining a uniting chamber into which all of said third passages of said second plate means discharge, said uniting chamber having a substantially funnel-shaped space converging to a single spinning orifice constituting a discharge opening of said uniting chamber for uniting said composite streams into an islands-in-a-sea stream and gradually reducing the diameter of said islands-in-a-sea stream without deformation.
 2. Apparatus according to claim 1, in which said first plate means comprises an upper plate in which said spinneret passages are formed, and a lower plate in which said second passages are formed, said upper and lower plates being contiguous face-to-face.
 3. Apparatus according to claim 1, in which the angle of convergence of said funnel-shaped space is at most 75*.
 4. Apparatus according to claim 1, in which said uniting chamber comprises a cylindrical space formed between the outlets of said third passages in said second plate means and said funnel-shaped space and satisfies the relation 15(1 - e X /50) < theta < 75 + 105(1 - e X /50) wherein X represents the height of said cylindrical space in mm and theta represents the converging angle of said funnel-shaped space in degrees.
 5. Apparatus according to claim 1, in which said second plate means has a plurality of fourth passages directly connecting said second space with said uniting chamber and located in an annular area of said second plate means surrounding the area in which said third passages are located, through which fourth passages said sea constituent polymer liquid is supplied to a peripheral portion of said uniting chamber.
 6. Apparatus according to claim 5, in which said second plate means has at least one fifth passage directly connecting said second space with a central portion of said uniting chamber.
 7. Apparatus according to claim 1, in which the outlet ends of said spinneret passages open concentrically into corresponding second passages.
 8. Apparatus according to claim 1, in which all of said spinneret passages have the same cross sectional area and said second passages located farther from the uniting chamber axis have a larger cross sectional area that those located nearer to said axis.
 9. Apparatus according to claim 1, in which all of said second passages have the same cross sectional area and said spinneret passages located farther from the uniting chamber axis have a smaller cross section than those located nearer said axis.
 10. Apparatus according to claim 1, in which outlets of said spinneret passages located farther from the uniting chamber axis are disposed eccentrically of corresponding second passages, the axes of said spinneret passages being offset inwardly from the axes of said second passages in a direction toward the uniting chamber axis.
 11. Apparatus according to claim 1, in which said tubes located farther from the uniting chamber axis have a larger inside cross sectional area than those located nearer said axis.
 12. Apparatus for spinning ''''islands-in-a-sea'''' type synthetic composite filaments composed of a plurality of synthetic polymeric filamentary constituents (island constituents) fully embedded in a synthetic filamentary constituent (sea constituent), comprising at least one spinning unit which comprises, in combination, a housing, a plurality of superposed plate means assembled in said housing and comprising first, second and third plate means with a first space above said first plate means and a second space between said first and second plate means, said first plate means comprising an upper plate having formed therein a plurality of spinneret passages corresponding in number and arrangement to the island constituents of said composite filament, and a contiguous lower plate having formed therein second passages in alignment with said spinneret passages into which said spinneret passages discharge, said second passages being of larger diameter than the discharge ends of said spinneret passages, means for supplying island constituent polymeric liquid to said first space to extrude streams thereof through said spinneret passages of said upper plate into said second passages of said lower plate, said second plate means having formed therein a plurality of third passages aligned respectively with said second Passages of said first plate means, tubes set in said second passages of said first plate means and extending through said third passages of said second plate means, said tubes having an external diameter smaller than the diameter of said third passages to provide an annular passage between each said tube and the respective third passage, means for supplying sea component polymeric liquid to said second space for extrusion through said annular passages, and said third plate means having a cavity therein defining a uniting chamber into which all of said tubes and annular passages discharge to form a composite stream comprising separate island constituent streams surrounded by sea constituent streams, said uniting chamber having a first portion of cylindrical shape into which all of said tubes and annular passages discharge without cross sectional area reduction and a second portion having a substantially funnel-shaped space converging into a single spinning orifice, the proportions of said uniting chamber satisfying the relation: 15(1 - e X /50) < < 75 + 105(1 - e X /50 wherein X represents the height of said cylindrical space in mm and theta represents the converging angle of said funnel-shaped space in degrees, whereby said composite islands-in-a-sea stream is reduced in diameter while maintaining the relation of said islands in said sea.
 13. Apparatus according to claim 12, in which the angle of convergence of said funnel-shaped space is at most 75*.
 14. Apparatus according to claim 12, in which said tubes are all of the same cross sectional area and said third passages are of different cross sectional areas, said third passages farther from the uniting chamber axis being larger than those nearer said axis. 